We have a reaction in equilibrium, if we apply any change in the reaction such as concentration, temperature and pressure, the equilibrium will shift. In the case of pressure, this property affects the gaseous phase, if we increase the pressure, the balance will shift to the side that contains fewer gaseous moles. If the pressure decreases, the equilibrium will shift to where there is a greater number of moles in the gas phase.
We see in the reaction that only compound C is in the gaseous phase, on the side of the products, therefore if the pressure increases, the equilibrium will shift to the opposite side, towards the reactants.
Answer: If pressure is added the direction of the reactions shifts will be to the reactants side.